1. Field of the Invention
The present invention relates to a multi power supply apparatus, and more particularly, to a multi power supply apparatus for driving light emitting diodes that is synchronized with a frequency of one output power of multi output power to control a switching of the multi output power and simplifies power conversion in supplying power for driving light emitting diodes.
2. Description of the Related Art
A power supply apparatus has so far been commonly used in information technology equipment such as a personal computer or the like, and home appliances such as an air conditioner, a stereo, a television or the like.
Such a power supply apparatus may supply a plurality of output powers depending on the electronic products to which the power supply apparatus is applied.
A general multi power supply apparatus converts an input DC power into separate AC powers through a single transformer and rectifies them again, thereby outputting a plurality of DC power. However, the general multi power supply apparatus affects other DC powers when the voltage level of one of the plurality of DC powers is changed by the single transformer, such that cross-regulation is not maintained. To this end, a buck chopper circuit is provided to an output terminal. However, power is reconverted by the buck chopper circuit after a primary power conversion, thereby degrading power conversion efficiency. Further, the number of components is increased due to the buck chopper circuit, such that manufacturing costs rise.
In addition, when a power supply apparatus is adopted for driving light emitting diodes, a boost circuit or a buck circuit is adopted so as to compensate for voltage deviation between light emitting diodes after the primary power conversion, thereby degrading power conversion efficiency. Further, the number of components is increased due to the boost circuit or the buck circuit, such that manufacturing costs rise.